Oil has been good to Crisby. With his $62,000 annual salary, he recently sold a starter home and purchased a $338,000, four-bedroom house a few doors from where he grew up. That's a significant achievement for a 20-year-old without a college degree and only a few years of work experience.

Now, with Chinese companies pouring hundreds of millions of dollars into the vast northern Alberta oil sand deposits, Crisby and others in this former Hudson Bay trading post believe the good days have just begun.

Crisby says he doesn't care who harvests the oil sands, as long as the paychecks keep rolling in.

"It's a free market," said Crisby, an Elijah Wood look-alike who rocks out to country tunes while hauling 400-ton truckloads of unprocessed sand for Syncrude, a giant Canadian oil producer.

To power its factories and fleets of new cars, China has intensified its search for oil in Asia and Africa. But Beijing's expansion into the United States' backyard demonstrates the risks the Asian economic giant is taking to secure energy supplies.

China's venture into Canada has triggered unease in Washington, where some fear it could threaten U.S. energy security and set the stage for clashes. Under the 1994 North American Free Trade Agreement, Canada ensured its role as the dominant supplier for the U.S. by guaranteeing it would send a portion of its energy south of the border. Today, Canada provides 17% of America's oil imports, 16% of its natural gas and nearly all its imported hydroelectric power.

Karen Harbert, assistant secretary for policy and international affairs at the U.S. Energy Department, said Washington didn't believe it should tell other countries where -- or with whom -- they can do business.

"Is China's investment into Canada's energy sector good for the North American energy market? Ultimately, it will be up to the Canadians to figure out which way they want to go and what's in their best interest economically and security-wise," she said.

In the last two months, China's three largest oil firms have announced major deals here, including a 40% stake in a $3.6-billion pipeline project.

The promise of a big new player in Alberta's oil sands has intensified a boom in the province. Since 2002, Fort McMurray's population has expanded by 20% to 56,000, mostly young Canadian men seeking their fortunes.

The two-lane highway heading south out of town turns into a virtual parking lot Thursday afternoons as thousands of workers head home to Edmonton and Calgary. Those who stay behind keep the cash registers ringing at places such as the Oil Can Tavern, a country bar that offers Latin dance lessons and check-cashing services.

Oil companies are beginning to import labor from as far away as Venezuela and China, which has sparked job-loss concerns among labor unions and indigenous leaders. But many Canadians, including Crisby, simply view China as another major player in an industry that has long been a global game.

Although the Canadian government owns the vast majority of the country's energy resources, more than half of Alberta's oil deposits are being developed by U.S. firms, including Chevron Corp., Exxon Mobil Corp. and Oklahoma City-based Devon Energy. The French, Dutch and Japanese also have invested in the oil sands.

Thanks in part to aggressive marketing by its political leaders, Canada has also been a big beneficiary of China's economic growth. China is now Canada's second-largest trading partner, and Chinese is the third-most widely spoken language in Canada, after English and French. More than a million people of Chinese descent have immigrated here in the last century.

There have been strains in the relationship. Before Hong Kong's return to Beijing's control in 1997, nervous Chinese pumped hundreds of millions of dollars into Canadian real estate and companies, triggering racial fears.

The latest influx of Chinese funds into energy and mining has prompted the Canadian government to look more closely at the national security effects of foreign investment.

Canada is closely watching the debate in Washington over competing bids for Unocal Corp. by Chevron and China's CNOOC Ltd., a majority of whose stock is held by government-owned China National Offshore Oil Corp. U.S. critics say a Chinese buyout of the California company would put scarce energy resources in the hands of a potentially hostile government.

Wenran Jiang, a China expert at the University of Alberta, said a U.S. rejection of the CNOOC bid would make Canadians more cautious about striking energy deals with the Chinese.

Energy analysts say Canada must balance its desire for investments from China with the need to satisfy its best customer, the United States, which buys 80% of Canada's total exports.